(doc) Update COMMITTERS and CONTRIBUTING

Without this patch the documentation describing our workflow and process
is out of date for Facter.  This is a problem because community
contributors and people new to Puppet Labs have a more difficult time
learning how to submit contributions and merge contributions into the
codebase.

This patch addresses the problem by copying the COMMITTERS and
CONTRIBUTING documents from Puppet and customizing them specifically to
Facter.

[ci skip]
(maint) Update link to the contributor license agreement

New link: http://links.puppetlabs.com/cla as per Eric.

[ci skip]
(maint) Remove unused facter.conf

Facter.conf is not used anywhere in facter and has not been modified in the
entire git history of facter. This commit removes the file and directory to
reduce clutter.
(packaging) Remove etc directory references from packaging

In commit d091bf882d731232ebcbf8d1dc324593cc837a98, facter.conf and the etc
directory were removed from facter. This commit removes the references to the
etc directory from the osx file mapping file and ext/project_data.yaml, which
is used to build the gem and tarball. Without this commit building the gem or
tarball will fail trying to copy a nonexistent directory.
Add output validation to facter
(FACT-134) Validate resolution output
(refactor) Remove double negation from resolution confine check
(maint) clean up Facter::Application#run

Move requires to top level, simplify how facts are sorted
Extract facter command line formatting, add plaintext option

This extracts facter's command line formatting to a separate file and
calls out plaintext formatting as a specific case. This allows us a
clean way of removing the plaintext behavior as we move towards
structured facts.